Tony Kurdzuk/The Star-LedgerView from above the Senate Chamber dais in this January 2010 file photo.

TRENTON — Democratic lawmakers flexed their muscles again today for Gov. Chris Christie, saying they would withhold approval of vital funding for transportation projects until the governor explains his long-term plan to pay for them.

Sen. Paul Sarlo said he wants to hear Christie’s plan to fix the state’s nearly broke Transportation Trust Fund — which finances road projects — before allowing a committee he leads to consider more borrowing that will get the state through March.

"He’s always claimed he’s not going to repeat mistakes of the past, [and] he’s been very critical of the legislature," Sarlo said today. "So before we give him another Band-Aid approach, we want to know what the permanent solution is."

The Democrats’ move came a week after Christie said he would halt work on a $8.7 billion train tunnel beneath the Hudson River — and after a Christie administration official said there were talks to use the tunnel money to fix the transportation fund. Democrats roundly slammed the potential transfer of the funding, calling the Access to the Region’s Core tunnel project essential for New Jersey’s future.

New Jersey is almost out of money to fix potholes and parkways, and needs both short-term and long-term fixes. Next year, the state will only be able to afford the debt payments on the $22.5 billion it owes.

It was unclear today exactly how much longer New Jersey would be able to pay for its road construction without the new borrowing. A spokesman for the state Treasury Department declined to comment.

Christie today said he was waiting to hear from his advisors on potential solutions for the fund, which has borrowed almost as much money as it’s allowed to under law.

Christie’s spokesman Michael Drewniak declined to answer which projects would be put in jeopardy if Democratic lawmakers do not meet to approve the borrowing, which includes up to $500 million in refinanced bonds to make room for $1.25 billion in new borrowing.

"We hope that we can work with Sen. Sarlo to meet current needs as we prepare our plan for the Transportation Trust Fund," Drewniak said.

Tom Wright, executive director of the Regional Plan Association, a transportation advocacy group, said the Democrats’ move was "like tossing a match into a gas tank to see if there’s anything in it."

"Playing brinksmanship with the governor at this time is a pretty risky business, because Access to the Region’s Core is such a critical project to the future of the state," he said. "I’m worried that the fewer options he has to restructure the trust fund, the more attractive it becomes for him to kill or delay ARC."